Safety device for elevators.



0.F.SHEPARD. SAFETY DEVICE FOR ELEVATORS.

- APPLICATION FILED NOV- 6, I916. LQ@%H@L Patented Jan. 22, 11918;

. "flhl iiTATEd PATEN T OFFT@E.

OSCAR F. SHEPARD, OF CINCINNATI, OHIO, ASSIGNOR TO THE WARNER ELEVATOR MANUFACTURING COMPANY, OF CINCINNATL OHIO, A CORPORATION OF OHIO.

SAFETY DEVICE FOR ELEVATOR$.

Application filed November 6, 1916.

To all whom it may concern:

Be it known that l, OsoAR F. SHEPARD, a citizen of the United States, and residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented a new and useful Improvement in Safety Devices for Elevators, of which the following specification is a full disclosure.

My invention relates to an improved safety device for elevators.

My invention has relation to an elevator in which there is a driving drum wound with a transmission cable, one end being attached to the elevator and the other to the counter-balance, and my purpose is to provide automatic means for preventing the cable from running off of eitherend of the drum by the process of shutting off the driving power at predetermined points in relation to the cable travel in directions parallel with the axis of the drum.

Of course, these predetermined points represent abnormal positions of the cable relative to the drum and so also serve to prevent the possibility of the elevator being driven or riding into abnormal positions. Preferably the power throw-out is electrically energized and preferably the drum is electrically driven, but it is not essential to the principles of this invention that either the automatic throw-out or the elevator be electrically energized.

The features of the invention will be more fully set forth in the description of the accompanying drawings, forming a part of this specification, in which 1- Figure l is a front elevation of the driving drum partly in section. Fig. 2 is an end view of the drum partly in section.

On the floor of the basement are two pillar blocks for supporting the drum, only one of which need be shown andin this block or pedestal 1 there is a bearin 2 supporting one end of the driving shaft 3, the other block and a bearing of course supporting the other end of the shaft.

The drum 4 is rigidly fixed to this shaft 3 so as to rotate therewith and the worm or spiral thread 5 is formed on the drum periphery constituting a cable way. As shown, there are six cables, each of which is wound two and a half times around the drum, one end 6 of which is connected to the elevator, and the other end 6 to the counter-balance. The normal position of Specification of Letters Patent.

Patented Jan. 22, 1918. Serial No. 128,688.

the transmission cable is substantially medial of the drum when the elevator is in the medial portion of its shaft length, and as the drum is driven the spiral of the drum will alternately shift the cables to the right and left, as the elevator goes up or down. In ordinary usage the cables will maintain their normal or medial position so that it is only under abnormal conditions and on comparatively infrequent occasions that. the automatic stop feature of my drum is functioned.

Occasionally these cables under abnormal stresses or unusually heavy weight dispositions will have say a winding section unusually taut, and the unwinding section of the cables corresphndingly lax or flexed, as where one weight is considerably greater than the other. Under these and other conditions occasionally obtaining, such as circumferential slippage incident to friction drive, there is a perceptible creepage tendency of the cable relative to the drum periphery or cable way, and the effect or influence of this creepage is'to cause the cable to travel in an axial direction of the drum a farther distance to one end or the other of the drum than the normal medial right and left limit of ordinary elevator operation.

If there were no provision on the drum for automatically limiting the cable travel axially of the drum, thecable would run off the end. I have provided a very simple and entirely depen able device for preventing such abnormal cable travel.

On one of the pillar posts is a casing 7 housing an electric switch, the source of electric supply not being shown, or the connections to the motor ordriving engine clutch, as the case may be. Incthe casing 7 is a switch lever 8 on the rock shaft 9, the switch member 8 being movable to the right and left over the insulating segments 10, the stationary contact 11 establishing the driving circuit being midway between the insulation segments 10. On the inner end of this rock shaft 9 is a rock arm 12 slightly bent inward to project into the open end of the drum in proximity to the periphery and constituting a member to be automatically tripped in abnormal or extreme cable positions. The member 8 might be a simple mechanical element, as a clutch lever, instead of a switch, if desired.

Under this web periphery of the drum,

at a selected place on its inner surface, are

consisting of a bell crank lever fixed to said rock shaft having an inwardly extending arm 16 held in predetermined position by a spring 17 interposed between said arm and the drum spoke 18, the other end 18 of the bell crank, lever projecting laterally and outwardly and having a lug l9 projecting radially through an aperture :20 formed in a predetermined cable way or thread, over which one of the end cables would travel in extreme or abnormal movements. To the the other end of shaft 15 is secured an arm 15' having a lug19' projecting through drum aperture 20. V

Laterally projecting from the end of bell crank arm 18 that is, in a direction parallelwith the axis of the drum, is a lug 21" constituting a trip to engage and coact with the rock arm 12 when, and only when, the lug 1.9 is moved inward by reason ofa cable having traveled beyond its normal position into an extreme-cable thread, and so en gaging the lug l9 and depressing arm 18.

As shown in Fig. 1, one of these apertures 20 and lug 19 are at the left end of the drum and the counterparts, aperture 20 and lug 19 are at the other end of the drum, determining the alternate abnormal or extreme positions of the cable where it is desired to automatically throw out the drive. The normal extremes of the cable travel axially of the drum are represented by the points 22, 22, in the threads or cable ways 23, immediately inside the cable ways 24, 24:, respectively, in which the apertures and lugs are positioned.

It will be readily understood that when the cable travels into these extreme threads .24, 24, the electric switch is operated and the power automatically thrown out, or the throwout might be a mechanical clutch, or

Copies of this patent may be obtained for the drive a motive force other than electricity, so far as concerns the broader phases of the invention.

\Vhile, as shown, the invention is specifir cally employed to stop the drum in abnormal or extreme cable positions, the principle of the invention in a broader phase might be employed to exercise a given control over the drum or operative influence in the normal drum function, as braking the drum or effecting a speed change of the drum. That is to say, the movement of the member to be tripped or finally actuated by a given lateral travel of the cable may be variously utilized or functioned in normal or regular functions, as well as under abnormal or emergency conditions. The principle may also be utilized in relation to cables attached to the drum as well as the friction drive type shown.

Having described claim:

In a device of the class described, a rotating drum peripherally formed with a spiral cable-way and with orifices for tripping dogs, a rock shaft within the drum adjacent the periphery, a pair of rock arms on the shaft near the opposite ends of the drum, having trip-dogs projecting through appropriate drum orifices in the cable travel limit portions of the cable-way, tension means holding the dogs normally in projecting position, a trip arm fixed to one of said rock members and projecting beyond the end of the drum an electric switch supported adjacent sai end of the drum having a member to be tripped positioned in the path of movement of the said trip arm.

In witness whereof, I hereunto subscribe my name, as attested by the two subscribing witnesses. I

my invention, ll

OSCAR F. SHEPARD.

EMMA SPENER.

five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

